FALCONI. HA WKS, ETC. 
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ORDER X. FALCONI. HAWKS, ETC. 
Sternum , stout and arched. Keel , high. Furcula , very strong and considerably arched. 
Head , wo£ /ar^e. 
Although some of the members of this Order resemble the Owls somewhat in external 
forms, they differ widely from them in many internal characters. The eyes in both orders 
are quite large but among the present birds, they are not directed quite so well forward, 
neither are they especially adapted for seeing by night. The bill, as in the Owls, is strong 
and curved but is not often concealed by bristly feathers. Usually there is no disk of 
feathers surrounding the face but this is occasionally present, notably among the species 
in Circus , in which genus the cavity of the ear is also large; yet this is not so remarkable 
in other Hawks. The tarsus is usually rather long and naked but is occasionally feath¬ 
ered, even to the toes. The wings are long and well formed but the plumage is compact, 
especially that by which flight is produced. The sternum is always strong, with either an 
unbroken margin or two or four marginal indentations. These are oftener closed than open 
but they differ widely in this respect, as will be seen under family and generic characters. 
The keel is quite high as a rule, although it does not always equal in height one half the 
width of the sternum and seldom exceeds it. The costal process is much smaller than in 
the preceding order. The coracoids are stout and of medium length, as in the Owls, and 
are set on at a wide angle but, unlike the latter named order, where the furcula is notice¬ 
ably weak and without a terminal expansion, in these birds, it is very strong, well arched, 
and has a slight terminal expansion. The scapula is similar in form to that of the Owls 
but is more inclined backward toward the sternum than in the latter named order, where 
it is set on at nearly a right angle with the coracoid. The manubrium is usually present 
but small. All this sternal structure indicates that its possessors are not only endowed 
with powerful flight but that they are capable of making very rapid and abrupt aerial 
evolutions. 
As in the Owls, the oesophagus is wide but in these birds, it is dilated into a crop of 
considerable size. The proventriculus is very well developed. The stomach is large but 
not muscular. Although the fold of the duodenum is quite long, the pancreas is not very 
large. There are two coeca but they are not very well developed, often, in fact, being 
rudimentary. The females are larger than the males. 
FAMILY I. MILVIDHA THE KITES. 
The sternum , about equals in width the length of the coracoids and the scapular process of 
the latter does not meet the furcula. Marginal indentations , two , inclosed. 
In this family, I have included a number of genera which, although they vary greatly 
in external form, agree in sternal characters' as given above. The manubrium is moder¬ 
ately well developed but is not forked. The farcula is stout, flattened by lateral expansion, 
wide and thick near the base which is abruptly truncated, not being produced into a point. 
The terminal expansion is small and the furcula near it is contracted, furrowed above, 
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